Capacitors are used in constant voltage supplies such as switching regulators and series regulators. A semiconductor circuit having a constant power supply uses a phase compensation capacitor in conjunction with a resistor to enhance stability in voltage regulation. The use of such a resistor-capacitor (RC) circuit compensates for phase shifts in output voltage.
Various methods have been proposed to provide a semiconductor circuit with an efficient RC structure. For example, a related-art semiconductor device having a resistor connected with a metal-insulator-metal (MIM) capacitor provides an RC structure with a reduced size. According to this method, at least one of upper and lower metal electrodes of the MIM capacitor uses a resistive metal plate of a given sheet resistance. The resistive metal plate integrally forms the capacitor electrode and the resistor, establishing a series RC circuit therebetween.
Although effective in reducing overall size of the semiconductor device, the above method cannot be used to provide a parallel RC circuit. Accordingly, a demand exists for a semiconductor device structure with a resistor and a capacitor designed to allow both parallel and series connections therebetween while achieving size reduction and excellent stabilizing performance of the RC circuit.